import React from 'react'; //引入react核心库
import ReactDOM from 'react-dom'; //引入react-dom
import './index.css'; //样式文件
import App from './App'; //所有组件的“外壳”组件
import reportWebVitals from './reportWebVitals'; //分析网页性能

ReactDOM.render(
  <React.StrictMode> {/* 开启api检测 */}
    <App />
  </React.StrictMode>,
  document.getElementById('root')
);

// If you want to start measuring performance in your app, pass a function
// to log results (for example: reportWebVitals(console.log))
// or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals
reportWebVitals(); //让网页性能分析工具开始工作
